Abstract : Significantly greater weight loss was observed in PFDA-treated rats than in pair controlled rats. These data indicate that the wasting syndrome cannot be explained entirely by lack of food intake. Additionally, a precipitous fall in serum thyroxine was observed as early as 12 hours following PFDA. Early experiments indicated that a hypothyroid-like state resulted from PFDA treatment. PFDA induced decreases in serum thyroid hormones, anorexia, bradycardia, hypothermia, as well as alterations in myocardial catecholamine metabolism. Liver enzymes alpha-glycerolphosphate dehydrogenase and malic enzyme were measures to evaluate tissue thyroid state, the activity of both enzymes was significantly elevated as early as 24 hours and remained so throughout the experiment. A possible conclusion based on interpretation of these data is the PFDA alters biochemical processes at the cellular level which produces confused messages concerning metabolic status, thus leading to anorexia and metabolic inefficiency which results in severe body wasting and hypothermia.